1. Field of the Invention
The present invention relates to hip pins and, more particularly, to an intramedullary hip pin and cortical plate especially adapted to resist loads and to permit weight to be applied without requiring long periods of healing.
2. Description of the Prior Art
A persistent problem with hip pins is that of preventing the hip pin from being forced through the head of the femur into the hip joint. As has been pointed out in the Hip Pin Patent, certain prior hip pins are in the form of narrow cones which extend through the neck of the femur on one end to a location adjacent the head. The pins are connected to plates extending along the femur and which are fastened thereto on the outside. Disadvantages of this type of prior hip pin construction include perforation of the head of the femur upon applying weight to the hip joint, poor distribution of forces from the pelvis which requires a relatively strong and large hip pin, and the inability to place weight on the fractured femur for an excessive period of time after the hip pin has been implanted.
The Hip Pin Patent represents an improvement over previous hip pin constructions. The pin includes a head portion having a saddle which corresponds substantially in shape to the neck of the femur so as to receive forces from the pelvis and distribute them relatively evenly. The head portion also includes a blunt nose facing the hip joint which resists movement of the head of the hip pin through the head of the femur. A shank formed substantially like a cone and having its pointed end downward is inserted into the medulla of the femur shaft and is secured to the head portion by a set screw.
Although the Hip Pin Patent represents an improvement over prior art devices, certain problems still have not been addressed. One of these problems relates to securing the hip pin within the head and neck of the femur so that not only is perforation of the head prevented, but rotation of the hip pin relative to the head and neck also is prevented. A continuing problem is that of anchoring the hip pin securely within the head and neck of the femur so that all relative movement between the hip pin and the femur is prevented.
An additional consideration which has not been adequately addressed by prior proposals relates to difficulties associated with inserting the hip pin into the head and neck of the femur and connecting the hip pin with a hip plate or shank. Complicated drilling and reaming operations sometimes are necessary, and it sometimes is difficult to properly maneuver the components of the hip pin assembly during implantation.
In view of the foregoing considerations, it is an object of the invention to provide a novel hip pin and coacting plate.
It is a further object of the invention to provide an intermedullary hip pin and cortical plate.
It is a still further object of the invention to provide a hip pin which resists being forced through the head of the femur.
It is a still further object of the invention to provide a hip pin which may be rigidly secured within the head and neck of the femur so that relative motion between the pin and femur is not possible.
It is a still further object of the invention to provide a hip pin and coacting plate requiring minimal drilling and manipulation of components for implantation.